How to Replace a Boiler Fan (UK, Gas Safe Guide)
Diagnose and replace a boiler fan on Worcester, Vaillant, Baxi, Ideal and Glow-worm combis. Fault code cross-references and OEM numbers.
Confirm the fan is at fault
Common fan fault codes: Worcester EA229, Vaillant F29 with no ignition sequence audible, Baxi E133/E168, Ideal Logic L2, Glow-worm F1. Before condemning the fan, check the Hall sensor voltage (typically 5 V) between the yellow and black leads at the PCB connector during a heat demand.
OEM fan cross-references
Fans are the most-superseded spare on modern boilers because motor suppliers change every 2–3 years. Always order the latest number — the mounting flange and PWM signal profile are unchanged, but the bearing life is significantly better.
- Worcester Greenstar i/Junior: 87161431020 (supersedes 87172043600).
- Vaillant ecoTEC plus 24/28/32: 0020219547 (supersedes 0020039222, 0020051763).
- Baxi 800 Combi 2: 720873101.
- Ideal Logic Combi 24/30: 175596.
- Glow-worm Ultimate3: 0020257021.
Fit and test
Replace the fan-to-heat-exchanger gasket every time — it hardens after one heat cycle and won't reseal. After refit, run the flue gas analysis check (CO/CO₂ ratio) as per Gas Safe TB 143 before signing off.
Frequently asked questions
- Do I need to reset the PCB after a fan swap?
- Worcester and Ideal auto-detect. Vaillant ecoTEC requires D.093 diagnostic code entry to re-pair the fan speed table.
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